Jaundice, also known as icterus, is a condition which is
characterised by a yellowish discolouration of the skin and the whites of the eyes.
It is a symptom or clinical sign, not a disease by itself. The yellow colouration is
caused by an excess amount of the bile pigment known as bilirubin in the body.
Normally, bilirubin is formed by the breakdown of haemoglobin during the
destruction of worn-out red blood cells. The pigment is then excreted by
the liver into the bile via the bile ducts.

Excess amounts of bilirubin in the body can be caused
by the overproduction of bilirubin, the failure of the liver cells to metabolise or excrete
the bilirubin produced, or a blockage of the bile ducts. Overproduction of bilirubin
may be caused by the destruction of an unusually large number of red blood cells,
which occurs in a condition known as haemolytic anaemia. In this condition the liver
cannot excrete the bilirubin which is formed more rapidly. This may occur in diseases
such as malaria, thalassemia, and haemolytic disease (due to destruction of the red blood cells) of
the new-born . Often, mild jaundice occurs as a common and normal condition in new-born babies
because at birth there is both a deficiency in the enzyme that helps to eliminate bilirubin
and also an increased breakdown of red blood cells (RBC) in the body. In babies, the
condition generally disappears within a few days after birth as the enzyme is formed in
the body. Sometimes, deficiency of this enzyme can also cause jaundice in adults.
Jaundice may also result from various diseases or conditions that can affect the
liver, such as hepatitis, cirrhosis, or cancer. A blockage of the bile ducts, may
cause jaundice. The ducts may be blocked by various factors including inflammation
and infection (cholangitis), gallstones (cholelithiasis), or cancer of the pancreas
or the common bile duct.

The clinical types of jaundice include haemolytic jaundice
which is due to the breakdown of RBC; hepatocellular jaundice caused by hepatic
pathology due to viruses, drugs, alcohol abuse, etc; and Cholestatic jaundice due
to biliary tract obstruction.

There are various strains of hepatitis viruses
including hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis
D (HDV), and hepatitis E (HEV). Viruses F and G also exist and may cause primary
hepatitis. HAV is transmitted by contaminated food and water and by the faecal-oral route;
HBV and HDV are transmitted by contact with bodily fluids, HCV by percutaneous exposure
to blood, and HEV, by contaminated water and by the faecal-oral route. Hepatitis
A is seen most often in children and young adults, but the incidence is rising
among those who are HIV positive. Hepatitis B affects all age groups and is
associated with blood transfusion. Hepatitis C accounts for most transfusion-related cases.
It is seen in all age groups. Hepatitis D is seen in individuals who are susceptible
to HBV or may be HBV carriers, such as haemophiliacs and IV drug users. The
disease manifestation is severe in children. Hepatitis E is seen primarily
among young adults in developing countries. It is most severe in pregnant women.
Congenital non-haemolytic hyperbilirubinemia such as Gilbert's Syndrome also
causes jaundice. Sometimes certain drugs such as chlorpromazine
(an anti-psychotic drug) may inhibit bilirubin excretion by the liver,
causing jaundice.

The main symptoms of jaundice are the characteristic yellowish
colour of the skin, sclera (whites) of the eyes, nail beds and tongue.
Other symptoms usually depend on the actual cause of the jaundice. In some types of jaundice,
bilirubin is excreted in the urine, which becomes yellowish brown in colour.
If the excretion of bile is obstructed, stools are almost white and the
digestion of fat is consequently impaired. If the jaundice has been present
for a long time, pruritis (intense itching) may occur. In jaundice, due to
obstruction, lipid deposits on the skin such as xanthelesmas on the eyelids
or xanthomas can develop. Some patients with jaundice may also have vomiting,
and abdominal pain, malaise, severe weakness etc. Complications include hepatic
failure with its attendant complications such as bleeding, vomiting
of blood, accumulation of fluid in the abdomen (ascites), and a condition called
hepatic encephalopathy where the patient has altered consciousness and
later coma. Fulminant hepatic failure and hepatic coma may often be fatal even
with treatment. Another complication of hepatitis is the development of cirrhosis
(due to destruction of the liver cells) and also conditions such as chronic active
hepatitis wherein the jaundice may persist for several months. The prognosis
in these conditions may be poor although the results are better with prompt
and effective treatment.

Diagnosis of jaundice requires blood tests,
which determine whether the liver is diseased, whether the bilirubin
is metabolised normally by the liver cells, and if there is any abnormal
breakdown and destruction of the red blood cells. Blood tests will also
indicate any obstruction present. Hyperbilirubenaemia (increased serum levels
of bilirubin) is present. The normal total of serum bilirubin is about 2-17 micro-mol/l(<1 mg/dl).
The urine is examined for the presence of bile salts, bile pigments and urobilinogen.
The faeces is examined for pale colouration, which usually indicates an obstruction to
bile excretion. The diagnosis of hepatitis is based on the clinical history and various
laboratory tests. In HAV, the stool is positive for the virus two to four weeks after
exposure, and the enzyme-linked immunosorbent assay (ELISA) shows a rise in HAV antibodies.
In HBV, serum antigen tests detect HBsAg, as well as a series of antibodies such as anti-HBe.
A serum test for HCV can also be done. A liver biopsy may be done, for indications of
cellular changes or pathology. Ultrasonogram can be done to examine the liver,
gallbladder, and bile ducts to detect obstructions and locate gallstones.
ERCP is done to detect abnormalities in the biliary tract and pancreas. Liver
function tests are done to detect hepatic abnormalities. For some pancreatic
pathologies, abdominal CT Scans or MRIs may be required.

Treatment consists mainly of treating the underlying cause
(if treatable) and in providing supportive therapy. The basic pathology or
disease responsible for the jaundice should be diagnosed and treated.
Obstructive jaundice can be relieved by removing the cause of the blockage
such as gallstones, by surgical intervention. Haemolytic jaundice is treated
by drugs that target the cause of the haemolysis (e.g., malaria), and by other
therapy such as blood transfusion. It is important to stop the intake of the
drugs or toxic chemicals or alcohol that may be responsible for the jaundice.
Proper diet and nutritional supplements are also important in preventing the
condition from worsening. Vitamin K injections may need to be given to prevent
bleeding.

The most important step in prevention of Hepatitis B infection is vaccination.
Three doses of the vaccine need to be given at intervals of one
month each or alternately two doses may be given at monthly intervals
followed by the third dose at the sixth month. The immunity lasts for
five years and booster doses are required after that period. It is
important to avoid causes of liver disease such as alcohol abuse,
drugs, and toxins. Prompt treatment of underlying hepatic disorders or
pathology is essential to prevent or minimise permanent damage to the liver.